"I hope to support our nominee, I hope to support his candidacy going forward," Ryan said in an interview with CNN's Jake Tapper on Thursday afternoon. "I'm just not ready to do that at this point. I'm not there right now."
A short time later, the presumptive Republican nominee responded with his own dig at the most powerful elected Republican in the country.
"I am not ready to support Speaker Ryan's agenda," Trump wrote in a statement. "Perhaps in the future we can work together and come to an agreement about what is best for the American people. They have been treated so badly for so long that it is about time for politicians to put them first!"
Ryan had repeatedly pledged to support the Republican nominee, telling reporters on March 1 that "my plan is to support the nominee."
But Ryan said today that Trump needs to unite conservatives around shared values and principles before he can back the real estate mogul.
"I think he needs to do more to unify this party," Ryan said. "At this point, I'm just not ready to jump in."